Method for placing payload in orbit by multifunctional launch vehicle of combined scheme with cruise liquid rocket engine system (lres), multifunctional launch vehicle of combined scheme with cruise lres and method of refining it

ABSTRACT

The invention relates to a space-rocket technology and can be used for placing both a pilot-controlled and unpiloted space craft in the earth&#39;s orbit. The inventive method consists in igniting-up cruising liquid-fuel rocket engines (LRE) of all assembly units, when the propulsion power of LRE of the side units is set to maximum and the LRE of the central unit is set relatively low.

This application is a divisional of U.S. patent application Ser. No.09/972,006, filed on Oct. 9, 2001, now U.S. Pat. No. 6,581,881 which wasa continuation of International Application No. PCT/RU00/00406 filed onOct. 13, 2000.

FIELD OF THE INVENTION

The invention relates to the field of rocket-space engineering and mayfind application during the development of rocket-space systems servingto place manned and unmanned spacecraft, and also other objects ofdifferent purpose, on a near-earth orbit.

BACKGROUND OF THE INVENTION

The modern development of space engineering requires the creation oflaunch vehicles which are capable of delivering spacecraft of differentpurpose and mass to near-earth orbits at a height of 180-34000 km. Wherethere is such a variety of tasks, the demand arises for the presence ofmultifunctional launch vehicles which are capable in the basic or otherarrangement of performing these tasks. Launch vehicles of a combinedscheme with a multiunit lower stage satisfy this requirement in the bestmanner. Appropriately selecting the rocket units of the lower stage, itis possible over wide ranges to change the characteristics of the launchvehicle as a whole, achieving their greatest correspondence to thelaunch program. The advantages of launch vehicles of the combined schemeare manifested to the greatest degree when one of the rocket units ofthe lower multiunit stage, mainly the central, works for a longer periodthan the other units. Launch vehicles of the combined scheme make itpossible to also optimize the ascent of spacecraft into a near-earthorbit.

A typical example of the use of a multiunit lower stage for placing apayload into a near-earth orbit is the “Ariane” project, in particular,“Ariane-5” (see, for example, Aviation Week and Space Technology, No.13, 1999, pp. 61, 64-65). The launch vehicle “Ariane-5” has a lowermultiunit assembly of rocket units, including a central rocket unit witha cruise LRES and two side rocket units with cruise solid propellantrocket engines (SPREs). The project provides for the use of two variantsof a central rocket unit and several variants of side rocket units withdifferent operating times and thrust level of the cruise engines. Anacceleration rocket unit and the head unit with the payload areconnected to the central rocket unit in accordance with a tandem scheme.At lift-off both SPREs and the LRES of the central rocket unit arefired. When operation of the SPREs ceases, the side rocket units arejettisoned and the launch vehicle continues acceleration with the aid ofthe cruise LRES of the central rocket unit. When the launch vehicle“Ariane-5” with an enlarged central rocket unit is used, it possible toplace a payload with a mass of from 8 tons to 12 tons into a near-earthorbit from the KURU cosmodrome. In order to ascend a smaller payload,for example, with a mass of 6 tons, another central unit with anothercruise LRES is necessary. Thus, when a typical construction of a launchvehicle of a combined scheme is used, it is possible, without changingthe central rocket unit, to change the mass of the payload being placedinto orbit by 1.5 times, which is a typical range of change of the massof the payload for a modern launch vehicle of the combined scheme.During the refinement of this launch vehicle, separate refinement of thecentral rocket unit and the side rocket units in all their variants isnecessary, and also the testing of different assemblies of the launchvehicle. Since different variants of the rocket units are used in theassembly of the launch vehicle, the refinement of the launch vehicle asa whole takes a large amount of time and requires large expenditures.Furthermore, operation of the launch vehicle is possible only afterrefinement of at least one assembly of the central and two side rocketunits. A substantial drawback of all launch vehicles of a combinedscheme, which use side rocket units with SPREs, is the increasedecological contamination of the atmosphere with compounds of chlorine,which are contained in large amounts in the products of combustion ofthe solid propellant. The increase in the energetic characteristics ofthe solid propellant results in additional contamination of theatmosphere with toxic products of the combustion of the solidpropellant.

Other variants of use of a combined launch vehicle for the ascent of apayload into a near-earth orbit are also proposed.

A method for placing a payload into orbit by a multifunctional launchvehicle of a combined scheme is known and disclosed in U.S. Pat. No.4,964,340, class 102/377, B 64 G 1/40, Oct. 23, 1990. In accordance withthis patent an acceleration rocket unit and a head unit with a payloadare mounted on a central rocket unit with a SPRE. A lower multiunitassembly of rocket units is formed by connection of from two to six siderocket units with SPREs to the central rocket unit in accordance with alaunch program. During lift-off of a launch vehicle with six side rocketunits, SPREs of four lift-off side rocket units are fired andacceleration of the launch vehicle begins. Prior to cutting off theaforesaid rocket units, SPREs of the two remaining side rocket units arefired, after which the four spent rocket units are jettisoned andacceleration of the launch vehicle is continued with use of two SPREs.Before they are cut off, the SPRE of the central rocket unit is firedand the two spent side rocket units are jettisoned. The rocket enginesof the acceleration unit are fired after operation of the SPRE of thecentral rocket unit has ended. The aforesaid method is realized in alaunch vehicle of a combined scheme, containing a lower multiunitassembly of rocket units with cruise SPREs, including a central andconnected thereto side rocket units and tandem secured on the centralunit transition compartment, acceleration rocket units and a head unitwith the payload, head domes of the side rocket units and a system forsecuring the side rocket units to the central unit. Two side rocketunits are connected to the central rocket unit in a pitch plane, forminga minimum assembly of a combined launch vehicle with three rocket unitsin the lower multiunit assembly. Two other variants of the launchvehicle, which realize this method, are formed by additionallyconnecting to the central rocket unit of the launch vehicle a minimumassembly of either two side rocket units, positioned in the pitch plane,or four side rocket units, positioned symmetrically relative to thepitch plane. The known technical solution makes it possible to use asingle-type SPRE for all the rocket units in the lower multiunitassembly, which significantly reduces the expenditures on placing thepayload into orbit. However, in this solution the energeticpossibilities of the lower multiunit assembly of rocket units is notused to the full extent, since during the first stage of operation ofthe launch vehicle a portion of the rocket units—three out of seven(more than 40%) for the variant with six side rocket units, does notparticipate in the process of creating thrust and is a passive massduring the first stage of placing the payload into orbit, which impairsthe engine weight efficiency of the launch vehicle and results in areduction of the mass of the payload to be placed in the near-earthorbit. During the realization of this method for placing a payload intoa near-earth orbit, higher loads will act on the launch vehicle as awhole and accordingly on the payload when the SPREs of the side rocketunits fire, they beginning to operate, for example, prior to terminationof operation of the SPREs of lift-off rocket units, since at the momentof firing the additional SPREs a thrust acts on the launch vehicle bothfrom lift-off SPREs and the thrust of the SPREs of two more side rocketunits. In spite of the fact that a single-type SPRE is used in therocket units, in this construction of the launch vehicle it is notpossible to use a standardized rocket unit, since in the case ofdifferent assemblies of the launch vehicle a central rocket unit isrequired with different positioning of the units for securing the siderocket units. During the refinement of this launch vehicle, in additionto refinement of the firing of rocket units with SPREs under on-groundconditions, refinement is necessary for firing these units underdifferent altitude conditions, as is presumed by the order of firingSPREs of the rocket units during the placement of the payload into theorbit with different assemblies of the launch vehicle. This launchvehicle is also not safe from the point of view of ecology, since ituses SPREs, the drawbacks of which were noted above.

A method for placing a payload into orbit by a launch vehicle of acombined scheme is also known and disclosed in British patent No.1114414, class B7W2, FIGS. 4-8, May 22, 1968. In accordance with thispatent, an acceleration rocket unit with a payload, which unit isselected in accordance with the launch program, is mounted on the lowerstage. The multiunit assembly of rocket units of the lower stage isformed by connection of single-type, delta-like in plan, modules withcruise LRESs to each other with the formation of a pyramidal assembly.The number of modules in the pyramidal assembly may change from four tosix depending on the launch program. During lift-off of the launchvehicle the cruise LRESs of all the modules forming the pyramid arefired. The cruise LRESs of all the modules operate with an identicalthrust and are cut off simultaneously when the propellant in all themodules of the lower multiunit stage is consumed. All the modules of thelower multiunit stage are jettisoned simultaneously prior to firing thecruise LRES of the acceleration unit. The described method is realizedin a launch vehicle of a combined scheme, comprising a lower multiunitassembly of rocket units with cruise LRESs and tandem connected theretoacceleration unit. The lower multiunit stage is formed from single-type,delta-like in plan, modules, which have a triangular cross section.Modules with a spread angle of triangular cross section, correspondingto the number of assembly modules being joined, are used in each of thepyramidal assemblies. The modules are connected to each other alongadjacent surfaces. The known technical solution makes it possible to usea single-type LRES for all the rocket units of the lower multiunitassembly, which significantly reduces the expenditures on the placementof the payload into orbit. In spite of the use of a single-type LRES inthe rocket units of the lower multiunit assembly, in this constructionof the launch vehicle it is not possible to use a standardized rocketunit, since a module rocket unit with a different angle of spread oftriangular cross section is required for different assemblies of thelaunch vehicle. During the placement of the payload into orbit with theuse of the method described in this patent with the simultaneous cutoffof all the cruise LRESs of the lower multiunit assembly of rocket units,the main advantage of a combined launch vehicle—the possibility for morelengthy operation of the central unit, disappears, bringing the combinedlaunch vehicle to the traditional tandem arrangement with a heavierlower stage. During the refinement of this launch vehicle, therefinement of each modification of the module rocket unit included inthe lower multiunit assembly of rocket units is necessary, whichsignificantly increases the expenditures on the development of thelaunch vehicle and the cost of placing the payload into a near-earthorbit.

A method of placing a payload into orbit by a launch vehicle of combinedscheme is also known and disclosed in U.S. Pat. No. 5,141,181, class244/172, Aug. 25, 1992. In accordance with this patent when a payload isbeing placed into orbit by a multifunctional combined-scheme launchvehicle with cruise LRESs in accordance with a launch program, tandempositioned rocket unit and head unit with the payload are connected tothe central rocket unit and a lower multiunit assembly of rocket unitsis formed by connecting two or three side rocket units to the centralrocket unit. At lift-off the cruise LRESs of the side and central rocketunits are fired and they are brought to the nominal thrust mode. In anon-emergency situation the cruise LRESs of the side and central rocketunits work together in the nominal thrust mode until the side rocketunits are separated from the central, wherein the LRES of the centralrocket unit works on a propellant supplied from tanks of the side rocketunits. When the propellant from the side rocket units is consumed, thelatter units are jettisoned, and the LRES of the central rocket unitcontinues to operate, using the propellant of the central rocket unit.The launch vehicle contains a lower multiunit assembly of rocket unitswith multiengine cruise LRESs, the assembly including a central andconnected thereto side rocket units, and an acceleration rocket unit anda head unit with the payload tandem secured on the central rocket unit.The launch vehicle is provided with a system for pumping propellantbetween the side rocket units and the central rocket unit. It ispresumed that the construction of the launch vehicle described in thepatent and the method for placing the payload into a near-earth orbitensures guaranteed placement of the payload into the orbit when amultiengine cruise LRES is used, even if there is failure of one of theengines or the whole LRES of the central or one of the side rocketunits, as a result of rational use of reserves of the propellant of thecentral rocket unit and the side rocket units in the cruise LRES engineswhich have retained their working capacity. In this invention, anincreased time of operation of the cruise LRES of the central rocketunit is provided as a result of its operation during the first stage onpropellant fed from the side rocket units, which results in a reductionof the reliability of placing the payload into orbit, since there is ahigh probability that a defect in the propellant pumping system willappear, especially in the detachable connections of the pipelinesbetween the rocket units. Another drawback of this invention is that itis impossible to standardize the side units and the central unit, sinceit is necessary to provide them with a different number of pumpingdevices, which makes the refinement of the launch vehicle more complex,since the units for each assembly need to be refined separately.

The method most similar to the claimed method in respect to thecombination of material features is the method for placing a payloadinto orbit by a multifunctional launch vehicle of a combined scheme withcruise LRESs, which has been realized in the Soviet Union with use ofthe launch vehicle “Vostok,” which is used to place manned and unmannedspace ships with a mass up to 5 tons in a near-earth orbit (see, forexample, Launch Vehicles, V. A. Aleksandrov, V. V. Vladimirov, R. D.Dmitriev, S. O. Osipov, Senior Editor Prof. S. O. Osipov, Moscow,Voenizdat, 1981, pp. 19-22, FIG. 1.2). The known method includesconnecting tandem positioned acceleration rocket units and a head unitwith a payload to a central rocket unit in accordance with the launchprogram and forming a lower multiunit assembly, of rocket units byconnecting side rocket units to the central rocket unit, firing atlift-off all the cruise LRESs of the side rocket units and the centralrocket unit, jointly operating the cruise LRESs of the central rocketunit and the side rocket units until the propellant of the side rocketunits is consumed, cutting off the cruise LRESs of the side rocket unitsand separating the side rocket units from the central rocket unit whilecontinuing operation of the cruise LRES of the central rocket unit untilthe propellant therein is consumed, cutting off the cruise LRES of thecentral rocket unit, separating the tandem positioned accelerationrocket unit and the head unit from the central rocket unit andsubsequently accelerating the head unit until its placement into orbit.

The launch vehicle “Vostok” itself comprises a lower multiunit assemblyof rocket units with cruise LRESs, which work on kerosene and liquidoxygen and have a significantly less effect on ecology as compared withthe SPREs used in the “Ariane-5” project. The lower multiunit assemblyof rocket units includes a central and connected thereto four siderocket units. A transition compartment, an acceleration rocket unit anda head unit with a payload are secured in tandem on the central unit.The launch vehicle is provided with a system for securing the siderocket units to the central unit. The side rocket units are providedwith head domes. The central rocket unit has a large size and large massas compared with the side rocket units and carries more propellant inits tanks, which ensures more lengthy operation of its cruise LRES. Thecruise LRES of the central rocket unit has an immovably securedfour-chamber main rocket engine and four steering rocket engines. TheLRES of each side rocket unit has an immovably secured four-chamber mainrocket engine and two steering rocket engines. Thus, the lower multiunitassembly of rocket units of the launch vehicle “Vostok” is assembled ofnonidentical rocket units. The refinement of the launch vehicle “Vostok”included selection of the size-mass characteristics of the centralrocket unit, side and acceleration rocket units and thrustcharacteristics of their cruise LRESs, designing and manufacturing theaforesaid rocket units, forming therefrom the lower multiunit assemblyof rocket units, ground-based and flight-structural tests to confirm thereliability of both separate rocket units and the launch vehicle as awhole. As in respect to the launch vehicle “Ariane-5,” during therefinement of the launch vehicle “Vostok,” separate refinement of thecentral rocket unit and the side rocket units is necessary withsubsequent testing in assembly, which occupies a lot of time andrequires large expenditures. Furthermore, operation of the launchvehicle “Vostok” is possible only after refinement of the arrangement ofthe central rocket unit and the side rocket units.

It is clear from the foregoing that the necessity exists for improvementof the method for placing a payload into orbit and an expendable launchvehicle with a changeable assembly, which would ensure the delivery intodifferent near-earth orbits of devices of different mass and purposewith the simultaneous reduction of the cost of placing the payload andthe reduction of the time necessary to develop a launch vehicle.

The object to the achievement of which the claimed invention is directedis to create a method for placing a payload into orbit by amultifunctional launch vehicle of a combined scheme with cruise LRESsand the launch vehicle itself, which ensure an expanded range of changeof the mass of the payload being placed into orbit with a minimum numberof varieties (types) of rocket units which are included in the assemblyof the launch vehicle. Another object to the achievement of which theclaimed invention is directed is to create a method for placing apayload into orbit by a multifunctional launch vehicle of a combinedscheme with cruise LRESs and the launch vehicle itself, ensuring aminimum change of the coordinates of descent of the spent side rocketunits when devices of different mass and purpose are placed into anear-earth orbit and accordingly a reduction of the dimensions of theclosed zone for the field of fall of spent rocket units.

An additional object of the invention is to create a method for placinga payload into orbit by a multifunctional launch vehicle of a combinedscheme with cruise LRESs, which ensures reduction of both inertial andaerodynamic loads on the launch vehicle during flight.

Another object of the invention is to create a launch vehicle ofcombined scheme with cruise LRESs, which ensures a reduction of theexpenditures on its development and on its production as a result of theuse of a minimum number of versions (types) of rocket units included inthe assembly of the launch vehicle and the increase of their massproduction.

One more object of the invention is to create a launch vehicle of acombined scheme with cruise LRESs and a method for its refinement, whichprovide a reduction of the expenditures on the development of the launchvehicle and the possibility of starting its operation in a lighterversion at the earliest stages of development.

DISCLOSURE OF THE INVENTION

The technical objects indicated above are achieved in that in the knownmethod for placing a payload into orbit by a multifunctional launchvehicle of a combined scheme with cruise liquid rocket engine systems(LRESs), including connecting tandem positioned acceleration rocketunits and a head unit with a payload to a central rocket unit inaccordance with the launch program and forming a lower multiunitassembly of rocket units by connecting side rocket units to the centralrocket unit, firing all the cruise LRESs of the side rocket units andthe central rocket unit at lift-off, jointly operating the cruise LRESsof the central rocket unit and the side rocket units until thepropellant of the side rocket units is consumed, cutting off the cruiseLRESs of the side rocket units and separating the side rocket units fromthe central rocket unit while continuing operation of the cruise LRES ofthe central rocket unit until the propellant therein is consumed,cutting off the cruise LRES of the central rocket unit, separating thetandem positioned rocket units and head unit from the central rocketunit and subsequently accelerating the head unit by the aforesaid rocketunits until its placement into orbit, in accordance with the invention,identical rocket units having adjustable cruise LRESs with an identicalnominal thrust are used to form the lower multiunit assembly of rocketunits, at lift-off the launch vehicle is made to ascend by cruise LRESsof the side rocket units at a nominal thrust, and the cruise LRES of thecentral rocket unit—at a thrust equal to 90-100% of the nominal value,and it is kept constant until the launch vehicle reaches a longitudinalacceleration of 12.7-16.7 m/sec² (1.3-1.7 g), then the thrust of thecruise LRES of the central rocket unit is reduced to 0.3-0.5 of thenominal thrust, and after the cruise LRESs of the side rocket units arecut off, the thrust of the cruise LRES of the central unit is increasedto the nominal value.

Furthermore, during operation of the launch vehicle with a lower levelof the thrust of the cruise LRES of the central rocket unit, when itreaches the longitudinal acceleration of 39-44 m/sec² (4-4.5 g), thethrust of the cruise LRESs of the side rocket units is smoothly reduced,maintaining the aforesaid longitudinal acceleration until termination ofoperation of the LRESs of the side rocket units.

Furthermore, during the atmosphere portion of the path, the altitude ofthe flight of the launch vehicle and its velocity are measured, on thebasis of which the dynamic pressure of the oncoming air flow at thedensity of a standard atmosphere at flight altitude is determined, andwhen the launch vehicle reaches the velocity at which the aerodynamicforces from the dynamic pressure of the oncoming air flow reach thevalues which are maximum permissible for the construction of the launchvehicle, further increase of the velocity of the launch vehicle iscarried out by adjustment of the thrust of the cruise LRESs of the siderocket units within the limits of 0.3-1.0 of the nominal thrust undercondition that the maximum permissible dynamic pressure is not exceeded,maintaining the relationship: $\begin{matrix}{V_{i} = {k\quad V_{1}\sqrt{\frac{\rho_{1}}{\rho_{i}}}}} & (1)\end{matrix}$

wherein:

V_(i) is the current velocity of the launch vehicle;

k is a dynamic coefficient equal to 0.95-1.05;

V_(l) is the velocity of the launch vehicle at which the maximumpermissible dynamic pressure is reached;

ρ_(l) is the density of standard atmosphere, at which the maximumpermissible dynamic pressure is reached;

ρ_(i) is the current density of standard atmosphere at the flightaltitude.

Wherein, the adjustment of the thrust of the cruise LRESs of the siderocket units is carried out under the condition that the maximumpermissible dynamic pressure, equal to 12000-17000 Pa, is not exceeded.

As applied to a multifunctional launch vehicle of a combined scheme withcruise LRESs, the stated object is achieved in a launch vehiclecomprising a lower multiunit assembly of rocket units with cruise LRESs,including a central and connected thereto side rocket units and tandemsecured on the central unit a transition compartment, accelerationrocket units and a head unit with a payload, head domes of side rocketunits, and a system for securing the side rocket units to the centralunit, in that in accordance with the invention, the lower multiunitassembly is composed of identical rocket units having identicalpropellant tanks and identical cruise LRESs with adjustable thrustssecured in a gimbal suspension, the side rocket units are mounted on thecentral rocket unit symmetrically relative to its longitudinal axis insectors formed by swinging, planes of the cruise LRES of the centralrocket unit so that the swinging planes of the cruise LRES of each siderocket unit are parallel to corresponding swinging planes of the cruiseLRES of the central rocket unit.

The launch vehicle may be provided with two side rocket units, which aremounted on the central rocket unit in one plane that is oriented at anangle of 45° to one of the swinging planes of the cruise LRES of thecentral rocket unit, or with four side rocket units mounted on thecentral rocket unit in two mutually perpendicular planes, oriented at anangle of 45° to the swinging planes of the cruise LRES of the centralrocket unit.

As applied to a method of refining a multifunctional launch vehicle of acombined scheme with cruise LRESs, the stated object is achieved in thatin a method for optimizing, including selecting the size-masscharacteristics of the central, side and acceleration rocket units andthe thrust characteristics of their cruise LRESs, designing andmanufacturing the aforesaid rocket units, forming therefrom a lowermultiunit assembly of rocket units, conducting ground-based andflight-structural tests to confirm the reliability of both separaterocket units and the launch vehicle as a whole, in accordance with theinvention, identical size-mass characteristics and thrust of the cruiseLRESs are set for the central rocket unit and the side rocket units,this ensuring use of the central rocket unit in the makeup of a launchvehicle of a tandem scheme with a monounit lower stage, the aforesaidrocket unit is produced and ground-based and flight structural teststhereof are carried out, including in the makeup of the launch vehicleof the tandem scheme, reliability of the central rocket unit isconfirmed and the central rocket unit refined on a launch vehicle of atandem scheme is used when forming the lower multiunit assembly ofrocket units of the launch vehicle of a combined scheme with theconduction of flight-structural tests with an increased time ofoperation of the cruise LRES of the central rocket unit relative to thecruise LRESs of the side rocket units.

The essence of the invention is that forming in the launch vehicle of acombined scheme the lower multiunit assembly of identical rocket unitshaving identical fuel tanks and identical cruise LRESs, it is possibleto expand the range of changing the mass of the payload placed in anear-earth orbit by simply increasing the side rocket units connected tothe central rocket unit. Wherein, as compared with known realizedschemes for placement of a payload by combined launch vehicles, in theclaimed method it is possible to significantly reduce the expenditureson placing the payload into orbit as a result of using monotypestandardized constructions. Using adjustable cruise LRESs in theaforesaid rocket units makes it possible at lift-off to fully realizethe energetic possibilities of the lower multiunit assembly of rocketunits, and subsequent reduction of the thrust of a cruise LRES of thecentral rocket unit to 0.3-0.5 of the nominal thrust guarantees thatthere is a reserve of propellant in the central rocket unit for itscruise LRES after separation of the side rocket units. A decrease of thethrust of the cruise LRES of the central rocket unit begins after alongitudinal acceleration of 12.7-16.7 m/sec² (1.3-1.7 g) has beenreached by the launch vehicle, this acceleration ensuring a stableposition of the launch vehicle in its path. An increase of the thrust ofthe cruise LRES of the central rocket unit to the nominal value afterthe cruise LRESs of the side rocket units are cut off makes it possibleto fully use the energetic possibilities of the central rocket unit.

A smooth reduction of the thrust of the cruise LRESs of the side rocketunits when the launch vehicle reaches a longitudinal acceleration of39-44 m/sec² (4-4.5 g) with the maintenance of this longitudinalacceleration until teinination of operation of the side rocket unitsensures expansion of the range of the mass of the payload placed intoorbit, since it provides the possibility of avoiding redundant overloadswhen a payload with reduced mass is being placed into orbit. Wherein, itis also possible to achieve a minimum change of the coordinates of thefall of spent side rocket units and accordingly—reduction of the closedzone.

The proposed method makes it possible to limit the action on the launchvehicle of aerodynamic forces from the dynamic pressure of the oncomingair flow. In order to do this, when the maximum permissible dynamicpressure on the construction of the launch vehicle is reached, a furtherincrease of the velocity is carried out by adjusting the thrust of thecruise LRESs of the side rocket units within the range of 0.3-1.0 of thenominal thrust under the condition that the maximum permissible dynamicpressure is not exceeded, maintaining the indicated relationship (I).

A dynamic pressure of the oncoming air flow, which does not exceed12000-17000 Pa, is the optimum dynamic pressure for the construction ofa launch vehicle of combined scheme.

Securing the cruise LRESs of the central rocket unit and the side rocketunits in a gimbal suspension and mounting the side rocket units on thecentral rocket unit symmetrically relative to its longitudinal axis insectors which are formed by swinging planes of the cruise LRES of thecentral rocket unit, so that the swinging planes of the cruise LRES ofeach side rocket unit are parallel to corresponding swinging planes ofthe cruise LRES of the central rocket unit, ensures an identicalpositioning of each side rocket unit and its cruise LRES relative to thecentral rocket unit and its cruise LRES independent of the number ofside rocket units included in the launch vehicle assembly, which makesit possible to use identical rocket units in the makeup of the launchvehicle with a standardized system for control of each side rocket unit.

When two or four side rocket units are secured on the central rocketunit with their arrangement in planes oriented at an angle of 45° to theswinging planes of the cruise LRES of the central rocket unit,identicalness of the conditions of their operation is ensuredindependent of the number of side rocket units in the lower multiunitassembly.

The proposed method for placing a payload in orbit by a multifunctionallaunch vehicle of a combined scheme with cruise LRESs and theconstruction of the launch vehicle provide the possibility of reducingthe cost of development of the launch vehicle and to begin its operationat the very earliest stages of development, since in the proposed methodof refinement, during the selection of the size-mass characteristics ofthe central, side and acceleration rocket units and the thrustcharacteristics of their cruise LRESs, identical size-masscharacteristics and thrust of the cruise LRESs are prescribed for thecentral and side rocket units. This provides the possibility of usingthe central rocket unit in the makeup of a launch vehicle of a tandemscheme with a monounit lower stage, which makes it possible after thecentral rocket unit has been manufactured and ground-based andflight-structural tests have been carried out to begin to use it withinthe makeup of a launch vehicle of a tandem scheme. After ascertainingthe reliability of the central rocket unit in this manner, the lowermultiunit assembly of rocket units of the launch vehicle of a combinedscheme is formed and flight-construction tests are carried out with agreater time of operation of the cruise LRES of the central rocket unitrelative to the cruise LRESs of the side rocket units.

The technical result from use of the proposed invention is the expansionof the range of change of the mass of the payload being placed in anear-earth orbit, in particular, the launch vehicle of a combined schemebeing developed within the “Angara” project provides the possibility ofrocketing a payload of from 14 tons to 28.5 tons. The use of the centralrocket unit, being developed in the “Angara” project, as a lower stageof a launch vehicle of a tandem scheme with placement of a payload witha mass of from 2 tons to 3.7 tons into a near-earth orbit is alsopossible.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the general view of the proposed launch vehicle, heavyclass;

FIG. 2 shows view A in FIG. 1;

FIG. 3 shows the section B—B in FIG. 2;

FIG. 4 shows the section c—c in FIG. 3;

FIG. 5 shows the general view of the proposed launch vehicle, middleclass;

FIG. 6 shows view D in FIG. 5;

FIG. 7 shows a scheme for placing a payload into orbit;

FIG. 8 shows a graph of change of the thrust of a cruise LRES of thecentral rocket unit;

FIG. 9 shows a graph of change of the thrust of a cruise LRES of a siderocket unit with control of an inertial load;

FIG. 10 shows a graph of a change of the thrust of a cruise LRES of aside rocket unit with control of an aerodynamic load;

FIG. 11 shows a launch vehicle of a tandem scheme, in which a centralrocket unit is used as the first stage.

DETAILED DESCRIPTION

A heavy-class launch vehicle comprises a lower multiunit assembly 1 ofrocket units, including a central rocket unit 2 and connected theretofour side rocket units 3. The lower multiunit assembly is composed ofidentical rocket units, which have identical propellant tanks 4 and 5.The propellant tank 4 of each rocket unit 2 and 3 has a volume of 46 m³and holds up to 36.5 tons of hydrocarbon fuel. The propellant tank 5 ofeach rocket unit 2 and 3 has a volume of 90 m³ and holds up to 96 tonsof liquid oxygen. The central rocket unit 2 is provided with anadjustable cruise LRES 6 with a nominal thrust of 196 tons (1920 kN) anda minimum thrust of 58 tons. The side rocket units 3 are provided withadjustable cruise LRESs 7. The cruise LRESs 7 are completely identicalto the LRES 6 of the central rocket unit 2 and their thrust may also beadjusted within the range of from 58 tons to 196 tons. The central andside rocket units are provided with reactive systems for roll control(not shown in the drawing). The cruise LRES 6 of the central rocket unitis secured in a gimbal suspension 8 with two mutually perpendicularswiveling axes, making it possible for the LRES 6 to swing in two planesI—I and II—II. The swinging planes divide the central unit 2 into fourvertical sectors. The side rocket units 3 are mounted on the centralrocket unit 2 symmetrically relative to its longitudinal axis in theaforesaid vertical sectors in two mutually perpendicular planes III—IIIand IV—IV, oriented at an angle of 45° to the swinging planes of thecruise LRES 6 of the central rocket unit.

The cruise LRESs 7 of the side rocket units are secured in gimbalsuspensions 9 with two mutually perpendicular swiveling axes, making itpossible for the LRESs 7 to swing in two planes, similar to the cruiseLRES 6 of the central rocket unit. The swinging planes of the cruiseLRESs 7 of the side rocket units are parallel to corresponding swingingplanes of the cruise LRES 6 of the central rocket unit. The gimbalsuspensions 8 and 9 are shown in FIG. 4 schematically, since theirconstruction is not the subject of the invention according to theinstant application and may use constructions of LRES gimbalsuspensions, which are known in rocket engineering.

The system for securing the side rocket units includes hinge powerjoints for fixing the side rocket units relative to the central rocketunit, which joints are positioned in lower 10 and upper 11 girders. Theconstruction of the fixation units is not given consideration in theinstant application. The side rocket units are provided with head domes12. A transition compartment 13, an acceleration rocket unit 14 and ahead unit 15, in which the payload with a mass of 24.5-28.5 tons to beplaced into near-earth orbit is arranged, are secured in tandem on thecentral rocket unit.

The proposed invention makes it possible, using a standardized centralrocket unit, to assemble a middle class launch vehicle of a combinedscheme as shown in FIGS. 5 and 6. The middle class launch vehiclecomprises a lower multiunit assembly 1 of rocket units, the assemblyincluding a central rocket unit 2 and connected thereto two side rocketunits 3. The central and side rocket units of this rocket in respect toconstruction and dimensions are completely identical to the rocket unitsof the heavy class launch vehicle and use the same adjustable cruiseLRESs with the thrust changed from 58 tons to 196 tons. The side rocketunits 3 are mounted on the central rocket unit symmetrically relative toits longitudinal axis and are positioned in one plane oriented at anangle of 45° to the swinging plane of the cruise LRES of the centralrocket unit.

As an example of realization of the method, consideration will be givento the placement of a payload with a mass of 26-28 tons into anear-earth orbit with the aid of a heavy-class launch vehicle. Thesequence of the steps of placing the payload with the aid of a launchvehicle of combined scheme, shown in FIG. 7, includes:

launching the launch vehicle with simultaneous operation of the cruiseLRESs of the central and the side rocket units (position E);

separating exhausted side rocket units from the central rocket unit(position F);

accelerating the launch vehicle with the aid of the cruise LRES of thecentral rocket unit (position G). At this step, the dome of the headunit is cast off;

firing the cruise LRES of the acceleration unit and separating it fromthe central rocket unit (position H);

moving the payload into orbit with the aid of the LRES of the head unit(position J).

In accordance with the launch program. the lower multiunit assembly 1 ofrocket units is formed, connecting four side rocket units 3 to thecentral rocket unit 2. An acceleration rocket unit 14 with a cruise LREShaving a thrust of 30 tons (294 kN) and a head unit 15 with the payloadare also connected to the central rocket unit.

At the lift-off, the cruise LRESs 6 and 7 of the central and side rocketunits are fired and each of them is brought to the nominal thrust of 196tons, obtaining a sum thrust at lift-off of 980 tons. Acceleration isbegun with the launch vehicle in a vertical position until a stableposition of the launch vehicle is reached on the path, after which aturn in the vertical plane begins. When a longitudinal acceleration of14.7 m/sec² (1.5 g) is reached, the thrust of the cruise LRES 6 of thecentral rocket unit begins to decrease and it is reduced to 58 tons (570kN). Further acceleration of the launch vehicle is carried out at aconstant thrust of 58 tons of the cruise LRES 6 of the central rocketunit right up to burnout of the propellant from the tanks of the siderocket units and cut-off of their cruise LRESs 7. This provides thepossibility at the moment of cutting off the cruise LRESs 7 of the siderocket units to retain in the tanks of the central rocket unit up to 18tons of hydrocarbon fuel and up to 49 tons of liquid oxygen, which issufficient to deliver the payload into a near-earth orbit. After thecruise LRESs 7 of the side rocket units are cut off, the thrust of thecruise LRES 6 of the central rocket unit is increased to the nominalvalue of 196 tons, while the exhausted side rocket units are separatedfrom the central rocket unit and acceleration of the launch vehicle iscontinued during operation of the LRES of the central rocket unit at thenominal thrust right up to burnout of the propellant from the tanks ofthe central rocket unit. A typical graph of change of the thrust R_(t)of the cruise LRES of the central rocket unit is shown in FIG. 8 inwhich a change of the longitudinal acceleration N_(x) of the launchvehicle is also shown. After cutoff of the cruise LRES 6 of the centralrocket unit, the latter is cast off, the LRES of the acceleration rocketunit 14 is fired and further placement of the payload into orbit iscarried out by the cruise LRES of the acceleration unit and, wherenecessary, by the rocket engine itself of the head unit 15.

During the placement of a payload with a mass of 23-24 tons into anear-earth orbit by a heavy-class launch vehicle, the necessity arisesto control the cruise LRESs of the side rocket units in order to reducethe inertial loads on both the construction of the launch vehicle and onthe payload. In order to solve this problem during the operation of alaunch vehicle with a thrust level of the cruise LRES of the centralrocket unit equal to 58 tons, when it reaches its longitudinalacceleration of 39-44 M/sec² (4-4.5 g), the thrust of the cruise LRESs 7of the side rocket units is uniformly reduced, maintaining the aforesaidlongitudinal acceleration until the end of operation of the LRESs of theside rocket units. The cruise LRESs 7 of the side rocket units make itpossible to adjust the thrust within the range of 30-100% of the nominalvalue of a similar cruise LRES 6 of the central rocket unit. A typicalgraph of chance of the thrust R_(t) of the cruise LRESs 7 of the siderocket units when the maximum permissible value of the longitudinalacceleration N_(x) is reached is shown in FIG. 9.

Adjustment of the thrust of cruise LRESs of the central and side rocketunits also provides the possibility to ensure selection of the area offall of exhaust side and central rocket units, since it makes itpossible, controlling the thrust of the cruise LRESs of these units towiden the variation of kinematic parameters of the launch vehicle at themoments of separating the side and central rocket units.

The necessity for adjustment of the aerodynamic loads acting on theconstruction of the launch vehicle may arise in the atmosphere portionof the path. In order to do this the altitude of the flight of thelaunch vehicle and its velocity are measured, in accordance with whichthe dynamic pressure Q_(t) of the oncoming air flow at the density of astandard atmosphere at the flight altitude is determined. When thelaunch vehicle reaches a velocity at which the aerodynamic forces fromthe dynamic pressure of the oncoming air flow reach the maximumpermissible values for the construction of the launch vehicle, furtherincrease of the velocity of the launch vehicle is accomplished byadjustment of the thrust of the cruise LRESs of the side rocket unitswithin the range of 0.3-1.0 of the nominal thrust under condition thatthe maximum permissible dynamic pressure is not exceeded, maintainingthe relationship (1). In the case of the launch vehicle being givenconsideration as an example, the maximum permissible dynamic pressureshould not exceed 13000-15000 Pa. A typical graph of change of thethrust R_(t) of the cruise LRESs 7 of the side rocket units whenadjustment of the aerodynamic load acting on the construction of thelaunch vehicle is made is shown in FIG. 10. The change of the dynamicpressure of the oncoming air flow in the absence of adjustment of thevelocity of the launch vehicle is shown by the dashed line in FIG. 10. Alimitation of the dynamic pressure of the oncoming air flow acting onthe construction of the launch vehicle provides the possibility ofincreasing the mass of the payload being placed into near-earth orbit.

Refinement of the launch vehicle is accomplished in the followingmanner. The size-mass characteristics of the central, side andacceleration rocket units and the thrust characteristics of their cruiseLRESs are selected, wherein identical size-mass characteristics andthrust of the cruise LRESs, ensuring the use of the central rocket unitin the makeup of the tandem scheme launch vehicle with a monounit lowerstage, are defined for the central and the side rocket units. In thevariant of a combined launch vehicle of heavy and middle class underconsideration, the following parameters were taken for the centralrocket unit:

thrust of the cruise LRES—196 tons;

diameter—2.9 m;

length (from the upper bottom of the oxidizer tank to the nozzle exitsection)—25 m;

takeoff mass with filled oxidizer and fuel tanks—142 tons.

These parameters make it possible to use the central rocket unit in alaunch vehicle of a tandem scheme as its lower stage to place a payloadwith a mass of from 2 tons to 3.7 tons into a near-earth orbit.

Similar characteristics were set for the side rocket units. Thecharacteristics of the acceleration and head units were set on the basisof the mass of the payload.

The aforesaid rocket units are designed and produced and theirground-based and flight-structural tests are carried out. The centralrocket unit is tested in the makeup of a launch vehicle of a tandemscheme and its use begins in a launch vehicle of a light-class tandemscheme to place payloads of from 2 tons to 3.7 tons into a near-earthorbit (FIG. 11). This makes it possible to rapidly obtain statistic datain order to confirm the reliability of a produced rocket unit and toreduce expenditures on the refinement of a combined launch vehicle,since both experimental and operating launches of the rocket unit willbe taken into account in the statistics. The rocket unit which has beenrefined on a launch vehicle of a tandem scheme is used during theformation of the lower multiunit of an assembly of rocket units of alaunch vehicle of a combined scheme, variants of which are shown in FIG.1 and FIG. 5. Flight-structural tests are carried out with an increasedtime of operation of the cruise LRES of the central rocket unit ascompared with the cruise LRESs of the side rocket units, this confirmingthe reliability of the launch vehicle of the combined scheme.

What is claimed is:
 1. A method for refining a multifunctional combined scheme launch vehicle with cruise LRESs, the method comprising the steps of: selecting size-mass characteristics of a central rocket unit and thrust characteristics of its cruise LRES; selecting characteristics of acceleration rocket units and thrust characteristics of their cruise LRESs; designing and manufacturing said rocket units, forming from said rocket units a tandem scheme launch vehicle having a monounit lower stage; conducting ground-based and flight-structural tests of the tandem scheme launch vehicles, wherein a level of adjustment of a thrust of the central rocket unit cruise LRES is set within a range of 0.3-1.0 of its nominal thrust; forming a lower multiunit stage from side rocket units which are identical by size-mass characteristics and thrust characteristics of the cruise LRES to the central rocket unit refined on the tandem scheme launch vehicle, wherein data obtained from tests of the tandem scheme launch vehicle with the monounit lower stage are used for confirming reliability of the side rocket units with the cruise LRESs of the combined scheme launch vehicle. 